JP5711225B2 - Method for treating acidic solution containing iodide ion and iron ion - Google Patents

Description

  The present invention relates to a method for leaching copper sulfide ore. More specifically, the present invention relates to a method for efficiently regenerating necessary iron (III) ions using iron-oxidizing microorganisms when leaching copper sulfide ore using iodide ions.

In general, the leaching form of copper sulfide ore by hydrometallurgy:
・ Leaching form by batch stirring reaction using sulfuric acid or hydrochloric acid;
・ Leaching form (heap leaching method) that collects the liquid dripping by gravity by supplying sulfuric acid or hydrochloric acid from the top of the laminated body; and ・ Leaching copper efficiently using bacteria such as iron-oxidizing microorganisms , Method of recovery (bioleaching)
Etc. are known.

  Among the copper sulfide ore hydrometallurgy, bioleaching method has been put to practical use for secondary copper sulfide ores such as chalcocite and copper indigo. However, primary copper sulfide ores such as chalcopyrite have very low solubility in inorganic acids. Therefore, when leaching is performed at room temperature using the bioleaching method, the leaching rate is very slow.

  In order to solve the above-mentioned problem of leaching rate, Japanese Patent Application Laid-Open No. 2011-42858 (Patent Document 1) mainly contains chalcopyrite and arsenite at room temperature in the presence of iodide ions and iron (III) ions as oxidizing agents. An example has been reported that the leaching of copper sulfide ore is promoted.

On the other hand, Japanese Patent Application Laid-Open No. 7-91666 (Patent Document 2) reports an example of removing iodine in a solution using active chlorine as an oxidizing agent for oxidizing iodine, activated carbon as an adsorbent, and an anion exchange resin. Has been. In the purification method of alkali metal chloride aqueous solution, as a representative method of removing iodine in the liquid, (1) adding chlorine, hypochlorous acid or chlorine water to a solution containing iodine and alkali metal chloride (2) There is a method in which iodide ions are oxidized into iodine molecules (I ₂ ), and (3) are passed through activated carbon and adsorbed on the activated carbon. Similarly, Japanese Patent Laid-Open No. 4-16554 (Patent Document 3) describes a method of removing iodine from a liquid using an oxidizing agent and activated carbon in an industrial salt electrolysis method.
Japanese Patent Publication No. 62-34681 (Patent Document 4) reports a method of using an ion exchange resin as a method for separating and recovering iodine from brine.

JP 2011-42858 Japanese Patent Publication No.7-91666 No. 4-16554 Shoko 62-34681

In the case of Patent Document 1, iron (III) ions are oxidized from iron (II) ions obtained as a result of the leaching reaction and / or from ferrous sulfate, which is an inexpensive chemical, using iron oxidizing microorganisms. It is economically desirable if it can be produced and supplied. It is also economically and environmentally desirable that the leached solution is repeatedly used as the leached solution without being discarded. However, iodine content has strong bactericidal properties. Therefore, it is difficult to regenerate iron (III) ions using iron-oxidizing microorganisms in the presence of iodine (that is, in leaching using iodine).
Patent Documents 2 to 4 describe methods for separating and removing iodine. However, the solution used in these iodine content removal examples is completely different from the leached solution of acidic copper sulfide ore containing metal ions such as iron and copper. Therefore, it is difficult to apply these methods as they are to the method of Patent Document 1. In these methods, a chlorine-based oxidizing agent that is highly toxic to microorganisms is used. Therefore, even if these methods can be applied as they are and the iodine content can be removed from the leachate of copper sulfide ore, the effects on the microorganisms by the chlorine-based oxidizing agent or chloride ions remain. Therefore, it is difficult to efficiently oxidize iron in the solution after removing iodine by using microorganisms.
Therefore, in view of the circumstances as described above, the object of the present invention is copper sulfide ore while efficiently regenerating iron (III) ions using microorganisms under conditions that are versatile at the actual operation level in leaching using iodide ions. It is to provide a method of leaching copper from.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that iodide ions and iron (II) ions are leached in the leaching using the iodine content of copper sulfide ore mainly composed of chalcopyrite or arsenite. When the acidic solution containing it is reacted in a reactor containing activated carbon and iron-oxidizing microorganisms, iron (II) ions in the solution are oxidized to iron (III) ions by iron-oxidizing microorganisms, and at the same time by iron (III) ions. It was found that the oxidized iodine content can be adsorbed on activated carbon and separated and recovered. The present invention has been completed based on such findings.

That is, the present invention includes the following inventions.
(1) A method for treating an acidic solution containing iodide ions and iron (II) ions, wherein the iron (II) ions in the solution are oxidized to iron (III) ions by an iron-oxidizing microorganism. And performing the step in the presence of activated carbon.
(2) Iodide ions are oxidized by iron (III) ions generated by the oxidation, and iodine molecules and / or triiodide ions generated by oxidation of the iodide ions are adsorbed on activated carbon in parallel. The method according to (1) above.
(3) An acidic solution containing iodide ions and iron (II) ions was obtained in a step of leaching copper from copper sulfide ore using a sulfuric acid solution containing iodide ions and iron (III) ions as a leaching solution. The method according to (1) or (2) above, which is a liquid after leaching.
(4) A solution containing iron (III) ions after removing activated carbon from the treated acidic solution obtained by the method described in (2) above, and / or obtained by the method described in (2) above. After recovering the activated carbon from the treated acidic solution, a solution containing iodide ions obtained by reducing iodine molecules and / or triiodide ions adsorbed on the activated carbon to iodide ions and releasing them from the activated carbon,
A method for leaching copper from a copper sulfide ore comprising using the copper sulfide ore as a leachate.
(5) The treatment method according to any one of (1) to (4), wherein the oxidation is performed in a fluidized bed reactor, and the activated carbon concentration in the solution is 10 times or more the iodine concentration by weight. Leaching method.
(6) The treatment method or leaching method according to any one of (1) to (5), wherein the iron-oxidizing microorganism is Acidithiobacillus ferrooxidans, and the oxidation is performed under atmospheric pressure.
(7) The iodine molecules and / or triiodide ions adsorbed on the activated carbon are reduced to iodide ions by using a solution containing sulfite ions to be released from the activated carbon, as described in (2) or (4) above. Treatment method or leaching method.

According to the method of the present invention,
(1) Iron-oxidizing microorganisms produce iron (III) ions from iron (II) ions. Producing iron (III) ions are iodide ions ^- by oxidizing iodine molecule (I ₂₎ and / or tri-iodide ion (I) ^- to produce a (I _3). The iodine molecule or triiodide ion is highly toxic to iron-oxidizing microorganisms. However, when activated carbon is added, iodine molecules (I ₂ ) and / or triiodide ions (I ₃ ⁻ ) are adsorbed onto the activated carbon. That is, (i) oxidation of iron (II) ions by iron-oxidizing microorganisms, (ii) oxidation of iodine by generated iron (III) ions, and (iii) adsorption of iodine to activated carbon in the same system simultaneously Get up to. This makes it possible to produce iron (III) ions efficiently and to separate and recover iodine.
(2) Further, by mixing iron (III) ions produced through the mechanism described in (1) above with a solution containing iodine, iodine molecules (I ₂ ) and / or serving as a catalyst for copper sulfide ore dissolution reaction. Alternatively, it is possible to construct a reaction system in which triiodide ions (I ₃ ⁻ ) are regenerated and constantly supplied.
As another method different from the present invention, a method is also conceivable in which the solution after leaching is recovered with iodine by activated carbon and then oxidized with microorganisms. However, in this case, in order to adsorb the iodine content on the activated carbon, it is necessary to oxidize the iodine content by adding an oxidizing agent such as iron (III) ion to the solution. Moreover, in order to reduce microbial toxicity, the amount of activated carbon must be 200 times or more by weight with respect to the iodine content. On the other hand, in the present invention, it is not necessary to add iron (III) ions to the leached solution before the iron oxidation treatment. Further, in the present invention, a large amount of activated carbon having a weight ratio of 200 times or more with respect to the iodine content is not required. Therefore, the present invention enables cost reduction and process simplification.
(3) The iodine content adsorbed on the activated carbon can be recovered by eluting with sulfite ions. By reusing the recovered iodine in the leachate, it is possible to further reduce costs and increase efficiency.
(4) Copper leaching from copper sulfide ores including chalcopyrite and arsenite can be carried out efficiently at low temperatures at a normal temperature.

The processing flow at the time of using activated carbon in a fluidized bed reactor in this invention is shown. The effect of reducing iodine toxicity to iron-oxidizing microorganisms when activated carbon of each concentration is added when the iodine concentration is 8 mg / L. The iodine toxicity reduction effect with respect to an iron oxidation microorganism at the time of adding activated carbon of each density | concentration when adding so that an iodine density | concentration may be 20 mg / L is shown.

The method of the present invention is a method for treating an acidic solution containing iodide ions and iron (II) ions. More specifically, it is a method for producing iron (III) ions from a solution containing iodide ions and iron (II) ions. Furthermore, the method of the present invention includes a method for separating and recovering iodine.
In one embodiment of the present invention, when oxidizing iron (II) ions in an acidic solution containing iodide ions and iron (II) ions to iron (III) ions using an iron oxidizing microorganism, In the presence.
In one embodiment of the present invention, activated carbon and an iron-oxidizing microorganism (for example, Acidithiobacillus ferrooxidans) are charged into a solution containing iodide ions and iron (II) ions (for example, an iron oxidation reactor). And aerobically).
By this reaction, iron (III) ions are produced, and at the same time, iodide ions are oxidized by iron (III) ions to generate iodine molecules and / or triiodide ions. Then, iodine molecules (I ₂ ) and / or triiodide ions (I ₃ ⁻ ) of the oxide are adsorbed on the activated carbon.
Therefore, one of the advantages of the present invention is that the toxicity of iodine oxide to iron-oxidizing microorganisms can be reduced and iron oxidation can be continuously performed, and the valuable iodine content is separated and recovered. is there.

  Further, in one embodiment of the present invention, a copper solution from copper sulfide ore is used by using a sulfuric acid solution containing iodide ions and iron (III) ions (for example, in excess of the iodide ions) as a leachate. Is used in the method of leaching (FIGS. 1A, a and e). Specifically, the solution obtained after the copper leaching step is reacted with activated carbon and an iron-oxidizing microorganism (for example, Acidithiobacillus ferrooxidans) (for example, aerobically in a reactor) (FIG. 1D). That is, while the iron (II) ion in the solution or the newly added iron (II) ion (FIG. 1b, for example, ferrous sulfate) is oxidized, the iodine content is simultaneously removed by activated carbon. Thereafter, the acidic aqueous solution containing iron (III) ions produced by using iron-oxidizing microorganisms can be used as a leachate of copper sulfide ore. Or it can mix with the aqueous solution containing the iodine content collect | recovered after adsorption | suction to activated carbon, and it can utilize as a leaching solution of a copper sulfide ore.

  The copper sulfide ore used in the method of the present invention contains chalcopyrite or arsenite. The copper sulfide ore may be a copper sulfide ore mainly composed of chalcopyrite or arsenite. Alternatively, the copper sulfide ore may be a copper sulfide ore partially containing chalcopyrite or arsenite. The content thereof is not particularly limited, but the copper sulfide ore used in the method of the present invention is a copper sulfide ore mainly composed of chalcopyrite or arsenousite in that the copper leaching effect by the method of the present invention is sufficiently obtained. Is preferred.

The method of the present invention can be used in any leaching form as long as it is a copper smelting process using a sulfuric acid solution as a leaching solution. For example, the leaching mode may be not only batch agitation leaching but also heap leaching or dump leaching in which copper is leached into sulfuric acid by spreading sulfuric acid after depositing ore.
Further, the temperature of leaching is not particularly specified, but heating is not particularly required, and leaching at room temperature is possible.

  It is considered that the dissolution / leaching of copper sulfide ore by the method of the present invention proceeds by a catalytic reaction with a series of iodine contents shown in the following (formula 1) and (formula 2).

2I ⁻ + 2Fe ³⁺ → I ₂ + 2Fe ²⁺ (Formula 1)

CuFeS ₂ + I ₂ + 2Fe ³⁺ → Cu ²⁺ + 3Fe ²⁺ + 2S + 2I ⁻ (Formula 2)

  When the sum of both sides of (Equation 1) and (Equation 2) above is taken and the iodine component is eliminated, the following (Equation 3) is obtained, which is a leaching reaction using iron (III) ions as an oxidizing agent for copper sulfide ore conventionally proposed. I know that there is.

CuFeS ₂ + 4Fe ³⁺ → Cu ²⁺ + 5Fe ²⁺ + 2S (Formula 3)

First, in the reaction of the formula (1), iodide ions (I ⁻ ) added to the leachate are oxidized by iron (III) ions (Fe ³⁺ ) to generate iodine molecules (I ₂ ).
Further, the iodine molecule (I ₂ ) generated by the reaction of the formula (1) reacts with the remaining iodide ion (I ⁻ ), so that triiodide ion (I ₃ ⁻ ) is also generated in the leachate.
At this time the iodine concentration in the leaching solution can be appropriately determined by the kind, shape, copper grade of sulfide ore to be reactive form and subject (Note "iodine concentration" herein includes not only I ₂ I ^- , I ₃ ^-, including any condition such as, means the total iodine concentration). However, the iodine concentration is preferably 100 mg / L to 300 mg / L shown in JP2010-24511 or 8 mg / L to 100 mg / L shown in JP2011-42858.

Moreover, as shown in (Formula 3), the leaching of chalcopyrite requires the supply of iron (III) ions as an oxidizing agent in an amount corresponding to chalcopyrite (CuFeS ₂ ). For continuous chalcopyrite leaching, it is necessary to supply iron (III) ions as a continuous oxidizing agent. However, iodine content is highly toxic to microorganisms.
Particularly when iron-oxidizing microorganisms are used, iodine molecules (I ₂ ) or triiodide ions (I ₂ ) or triiodide ions (I ₂ ) or triiodide ions that are oxidized by iron (III) ions that also produce iodide ions that are not highly toxic to microorganisms. I ₃ ⁻ ). Therefore, it has been found that even when the iodide ion concentration in the solution is only 1 ppm, it is difficult to produce iron (III) ions by oxidation using an iron-oxidizing microorganism.
In a typical embodiment of the present invention, the activated carbon and the iron-oxidizing microorganism are introduced into the solution after leaching in the same reaction system. By this input, it is possible to produce iron (III) ions by the iron-oxidizing microorganism in the same system while removing iodine that is highly toxic to the iron-oxidizing microorganism from the leached solution.

In the present invention, the oxidation of iron (II) ions in the solution obtained after the copper leaching step and the adsorption of iodine to the activated carbon are preferably performed in parallel in a fluidized bed reactor containing activated carbon and iron-oxidizing microorganisms. (FIG. 1D). In addition, the activated carbon concentration is preferably 10 times or more, more preferably 13 times or more by weight ratio with respect to the iodine concentration in the solution before charging. Moreover, although it does not specifically limit about the upper limit of activated carbon density | concentration, From viewpoints, such as cost, it is 1000 times or less by weight ratio, for example, typically 700 times or less or 150 times or less.
The material for removing iodine is preferably a material having the ability to adsorb iodine by hydrophobic interaction.
Therefore, it is also possible to use a solid having a hydrophobic surface other than activated carbon, such as coke or hydrophobic resin. However, activated carbon is particularly excellent because of its high specific surface area and high iodine content removal ability.

  The type and raw material of activated carbon used in the present invention are not particularly defined. However, activated carbon having a large surface area, suitable for use in a liquid phase and excellent in stability is preferred. Moreover, the shape of activated carbon is preferably granular or spherical. For example, Taihei Chemical Industry's palm coal Mc, Nihon Enviro Chemicals white birch X7000H can be used.

Moreover, the iron (II) ion concentration in the solution which is the subject of the present invention is not particularly specified. However, a range of 0.2 g / L to 10 g / L is preferable as a range in which the growth of the iron-oxidizing microorganism is good. The concentration range of the iron (II) ions is also suitable as the concentration of iron (II) ions in the solution after leaching from the copper sulfide ore. The concentration range of iron (II) ions is the concentration of iron (II) ions necessary for mixing a solution containing iron (III) ions to be produced with an iodine-containing solution and using it as a leachate of copper sulfide ore. Is also appropriate.
Moreover, the iodine concentration in the solution which is the subject of the present invention is not particularly specified. However, the effect of the present invention can be exerted only when the concentration shows the growth inhibition of iron-oxidizing microorganisms when no activated carbon is added. And the density | concentration which shows growth inhibition is 0.5 mg / L or more in general.

Further, the iodine content adsorbed on the activated carbon can be recovered and reused by chemicals, heating, combustion treatment, and the like. In particular, in the present invention, the activated carbon adsorbed with iodine content (for example, iodine molecules and / or triiodide ions) is treated and eluted with a solution containing sulfite ions, so that the iodine content adsorbed on the activated carbon is reduced to iodide ions (I ^- ) Can be reduced and released (FIG. 1c). A solution containing iodide ions (I ⁻ ) can be reused for leaching copper sulfide ore. Alternatively, a solution containing iodide ions (I ⁻ ) can be mixed with an acidic solution containing iron (III) ions (FIG. 1a) and reused for copper sulfide ore leaching again (FIG. 1e). Of course, a new iodide ion-containing solution may be replenished when reused (FIG. 1d).
It is preferable to collect | recover iodine content using the solution containing 1 to 100 times sulfite ion by weight ratio with respect to the iodine content eluted at this time. It is more preferable to use a solution containing 33 to 100 times sulfite ions.

When copper is recovered from the solution after the copper leaching step (FIGS. 1B, C and f), generally a solvent extraction method using an extractant that selectively extracts copper is used. In rare cases, cementation is used.
These methods can be carried out at any stage, such as before or after the iodine recovery / iron oxidation process (FIG. 1D) in the present invention.
An example of the process flow of the present invention including the solvent extraction step is shown in FIG. FIG. 1 is an example of a fluidized reactor using activated carbon and iron-oxidizing microorganisms. The process need not be limited to a serial flow as shown in FIG. 1, and can be installed in parallel by bypassing the copper extraction step or iodine content recovery / iron oxidation step.
In practice, an optimum process flow may be applied in consideration of the influence of the extractant such as microbial toxicity.

The iron-oxidizing microorganism used in the present invention is not limited in its species as long as it has iron-oxidizing ability. Specifically, Acidithiobacillus ferrooxidans; Acidimicrobium ferrooxidans; microorganisms belonging to the genus Leptosprillum; microorganisms belonging to the genus Ferroplasma; or microorganisms belonging to the genus Acidiplasma can be used.
Among them, Acidithiobacillus ferrooxidans is preferable for the present invention because it can oxidize iron at normal temperature and pressure. As an example, Acidithiobacillus ferrooxidans FTH6B can be used. The FTH6B has been deposited at the National Institute of Technology and Evaluation Patent Microorganisms Deposit Center under the deposit number NITE BP-780.

Moreover, what is necessary is just to use the conditions suitable for each microorganism also about the temperature and pressure at the time of iron oxidation reaction.
When using the above Acidithiobacillus ferrooxidans, it is desirable to carry out under atmospheric pressure. Moreover, about temperature, it is desirable to implement in the range of 20-40 degreeC.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these.

(Example 1) Production of iron (III) ions by iron-oxidizing microorganisms in the presence of activated carbon in a solution containing iodide ions and iron (II) ions.
(1) 25 mL of a solution having the following composition, adjusted to pH 2.0 with sulfuric acid, was dispensed into an Erlenmeyer flask (50 mL capacity).

Fe ²⁺ 6g / L
(NH ₄ ) ₂ SO ₄ 3 g / L
K ₂ HPO ₄ 0.1 g / L
MgSO ₄ 0.4 g / L
Ca (NO ₃ ) ₂ 0.01 g / L


(2) Potassium iodide (KI) and activated carbon (Yaikol Mc, manufactured by Taihei Chemical Industrial Co., Ltd.) were added so as to satisfy the conditions shown in Table 1 below.
(3) After lightly stirring, the iron-oxidizing microorganism FTH6B was added to a bacterial concentration of 2.5 × 10 ⁶ cells / mL.
(4) These were gently shaken at a temperature of 30 ° C. and atmospheric pressure to promote iron oxidation by iron-oxidizing microorganisms.

The iron (II) ion concentration in the solution after microbial treatment under each condition was measured by a redox titration method using potassium dichromate. The total iron ion concentration including iron (II) ions and iron (III) ions was measured with an ICP emission spectroscopic analyzer (ICP-AES). The difference between the total iron ion concentration and the iron (II) ion concentration was calculated as the iron (III) ion concentration.
The change with time of the iron (III) ion concentration is shown in FIGS.
In the graph of FIG. 2, treatment condition A indicates iron oxidation by iron-oxidizing bacteria in a solution that does not contain iodine. On the other hand, treatment condition B shows iron oxidation by iron-oxidizing bacteria in a solution with an iodine concentration of 8 mg / L. Comparing treatment conditions A and B, it was shown that iron oxidation by iron-oxidizing bacteria was remarkably suppressed by the presence of iodine content.
Treatment conditions C to G show iron oxidation by iron-oxidizing bacteria when activated carbon is further added to the solution of treatment condition B in the range of 0.01 g / L to 5 g / L. Comparing treatment conditions AB with treatment conditions C-G, it was shown that iron oxidation was restored by the addition of activated carbon. In particular, when the amount of activated carbon with respect to the iodine concentration was 13 times or more by weight (treatment conditions D to G), it was shown that iron oxidation was significantly recovered.
In the graph of FIG. 3, treatment condition H indicates iron oxidation by iron-oxidizing bacteria in a solution having an iodine concentration of 20 mg / L. Treatment conditions I to M represent iron oxidation by iron-oxidizing bacteria when activated carbon is further added to the solution of treatment condition H in the range of 0.01 g / L to 5 g / L. Comparison of treatment conditions H and treatment conditions I to M showed that iron oxidation was recovered by addition of activated carbon. In particular, when the amount of activated carbon relative to the iodine concentration was 25 times or more by weight (treatment conditions K to M), it was shown that iron oxidation was significantly recovered.
In addition, the iodine concentration in the solution after microbial treatment was measured using an ICP mass spectrometer (ICP-MS). As a result, it was as shown in Table 1. Under the condition where activated carbon was added, the iodine content was almost in the liquid. Was not adsorbed by the activated carbon.

  From the results of FIG. 2 and FIG. 3, by reacting an acidic solution containing iodide ions and iron (II) ions in a reactor containing activated carbon and iron-oxidizing microorganisms, iron (II) in the same solution is obtained. It has been shown that ions can be oxidized to iron (III) ions by iron-oxidizing microorganisms. Furthermore, the results shown in Table 1 indicate that iodine oxidized by iron (III) ions can be adsorbed on activated carbon and separated and recovered.

(Example 2) Recovery of iodine content adsorbed on activated carbon in the presence of activated carbon in a solution containing iodide ion and iron (II) ion (1) Example 1 (1) containing 6 g / L of iron (II) ion ) Was added to a 500 mL Sakaguchi flask.
(2) Potassium iodide was added at 25 mg / L and activated carbon at 1 g / L.
(3) After lightly stirring, the iron-oxidizing microorganism FTH6B was added to a bacterial concentration of 2 × 10 ⁷ cells / mL.

(4) The mixture was gently shaken at 30 ° C. and atmospheric pressure to promote iron oxidation by the iron-oxidizing microorganism.
(5) The solution after microbial treatment was filtered to recover a precipitate containing activated carbon.
(6) To the recovered precipitate, 100 mL of 24 mM sulfite water (2 g / L, 33 times by weight with respect to iodine content) was added.
(7) After stirring at room temperature for 1 hour, the eluted iodine content was quantified using an iodine electrode in accordance with the method described in Japanese Patent Application No. 2009-245771. Specifically, by adding an appropriate amount of zinc powder, iodine content existing as iodine molecules and triiodide ions were all reduced to iodide ions, and then measured using an iodine electrode.
As a result, the iodine concentration was 32 mg / L, and it was confirmed that the iodine content was eluted. By reacting an acidic solution containing iodide ions and iron (II) ions in a reactor containing activated carbon and iron-oxidizing microorganisms according to this example, the activated carbon is adsorbed with iodine, and the activated carbon is recovered. It was shown that the iodine content adsorbed on the activated carbon can be recovered in the solution by treating the activated carbon with sulfurous acid.

  From the results of Examples 1 and 2, it is possible to prepare an aqueous solution containing iron (III) ions and an aqueous solution containing iodide ions from a solution containing iron (II) ions and iodide ions, respectively. Indicated. Furthermore, it has been shown that if a solution prepared by mixing them in an appropriate concentration and mixed is used for leaching of copper sulfide ore, leaching of copper from the copper sulfide ore can be promoted.

Claims (7)

  A method for treating an acidic solution containing iodide ions and iron (II) ions, comprising oxidizing iron (II) ions in the solution to iron (III) ions by an iron-oxidizing microorganism. A method of performing the step in the presence of activated carbon.   2. Iodide ions are oxidized by iron (III) ions generated by the oxidation, and iodine molecules and / or triiodide ions generated by oxidation of the iodide ions are adsorbed on activated carbon in parallel. The method described in 1.   The post-leaching solution obtained in the step of leaching copper from the copper sulfide ore, wherein the acidic solution containing iodide ions and iron (II) ions is a sulfuric acid solution containing iodide ions and iron (III) ions. The method according to claim 1 or 2. A solution containing iron (III) ions after removing activated carbon from the treated acidic solution obtained by the method according to claim 2, and / or a treated acidic solution obtained by the method according to claim 2. After recovering the activated carbon, a solution containing iodide ions obtained by reducing iodine molecules adsorbed on the activated carbon and / or triiodide ions to iodide ions and releasing them from the activated carbon,
A method for leaching copper from a copper sulfide ore comprising using the copper sulfide ore as a leachate.   The treatment method or leaching method according to any one of claims 1 to 4, wherein the oxidation is performed in a fluidized bed reactor, and the activated carbon concentration in the solution is 10 times or more the iodine concentration by weight.   The treatment method or leaching method according to any one of claims 1 to 5, wherein the iron-oxidizing microorganism is Acidibiobacillus ferrooxidans, and the oxidation is performed under atmospheric pressure.   The treatment method or leaching method according to claim 2 or 4, wherein iodine molecules and / or triiodide ions adsorbed on the activated carbon are reduced to iodide ions by using a solution containing sulfite ions to be released from the activated carbon. .

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